The invention relates to a tilting mount for controlling the angular or rocking displacement of a support member relative to a base. More particularly the invention relates to a tilting mount that joins the support member and base where the mount comprises an outer elastomeric member and an inner sleeve having an integral flange member, and whereby the angular displacement of the support member is controlled by further compressing diagonally opposed portions of the elastomeric member between the base and a rigid cup that overlays the elastomeric member.
Tilting mounts are typically used in chairs such as those used as office furniture and such mounts facilitate and control the fore/aft and side-to-side rocking, tilting or angular displacement of a support member that joins the seat and base.
Known mounts for facilitating and controlling the angular displacement of the support member typically include complex mechanisms and a large number of component parts to produce the desired angular displacement and to limit such displacement to a predetermined acceptable range of motion. Due to the complexity of such known tilting mounts, the prior art mounts are typically difficult and expensive to manufacture, assemble and repair; and the manufacture, assembly, and repair of such prior art mounts is time consuming.
Prior art tilting mounts are subjected to both tensile and compressive forces. The tensile forces can significantly reduce the useful life of the mount. The tensile forces are frequently caused by the rigid connections between one or more of the mount component parts and an outer mount housing. In mounts with such connections, the mount is continuously subjected to tension forces.
In known rocking or tilting mounts, mechanical stops are used to limit the angular displacement or rocking angle of the seat support member. By their nature the mechanical stops and also the mounts themselves have a limited useful life, and over time the mechanical stops and mounts wear out. Frequently, the prior art tilting mounts do not include a backup means for limiting motion of the mount in the event the mechanical stop fails. Without backup means the possible support member displacement angle may become unlimited or the support member may become disconnected from the mount.
The foregoing illustrates limitations known to exist in present devices and methods. Thus, it is apparent that it would be advantageous to provide an alternative mount directed to overcoming one or more of the limitations set forth above. Accordingly, a suitable alternative tilting mount is provided that eliminates mount tension forces, and includes a simple mount design, means for limiting angular displacement of the support member and means for preventing disconnection of the support member and base in the event of a mount failure, as well as other features more fully disclosed hereinafter.
In one aspect of the present invention this is accomplished by providing a tilting mount that eliminates complex mechanisms of prior art mounts by providing a mount that comprises a tubular sleeve member having an outer wall and an outwardly directed flange along the outer wall, and also includes an elastomeric member that substantially covers the sleeve member, the elastomeric member has an outer surface and a number of protuberances along the outer surface. The mount may be included as part of a support assembly that includes a base defining a cavity adapted to receive the mount, and a rigid cup that overlays the mount and precompreses the elastomeric member when the cup is fastened to the base. A moveable member is supported by the mount.
The mount is not connected to either the cup or base and is maintained entirely in compression. The mount is not subjected to tension either as assembled or when the support member experiences angular displacement relative to the base. Therefore the mount of the present invention is likely to have a longer useful life than other prior art tilting mounts.
As the member is displaced angularly, the compressive forces in diagonally opposed portions of the elastomeric member are increased while other elastomeric portions of the mount are moved out of compression. Angular displacement of the member is limited by snubbing of the elastomeric member between the inner sleeve and the base cavity.
The cup member has an upper opening that defines a minimum diameter and the sleeve flange defines a maximum diameter, and in all instances, the maximum diameter is greater than the minimum diameter. If the mount fails, an interference between the maximum and minimum diameters is created preventing egress of the sleeve and support member from the cup. The interference between the maximum and minimum diameters prevents the support member from disconnecting from the base. Additionally, the angular displacement of the support member is limited by the interference.